Born in Newport News, Virginia, Maguire is best known for his stage performance as Enjolras in the Broadway version of Les Misérables for which he won several awards including a Tony Award in 1987, a Drama Desk Award, and a Theatre World Award and as Count Carl-Magnus Malcolm in the 1990 version of A Little Night Music. He graduated from the University of Michigan in Ann Arbor with a Masters Degree and started a stage career in 1985 after he worked as a broker for several years. Maguire was married to actress Marita Geraghty with whom he has two daughters.